Printer Heat Recovery Mechanism

ABSTRACT

A print engine is disclosed. The print engine includes a fusing system having a heat pipe to recover heat generated by the fusing system and transfer the recovered heat back into the fusing system.

FIELD OF THE INVENTION

The invention relates to the field of printing, and in particular, toproviding energy efficiency in a printing system.

BACKGROUND

Printers are common peripheral devices attached to computers. A printerallows a computer user to make a hard copy of documents that are createdin a variety of applications and programs on a computer. Laser printersemploy a xerographic printing process to produce high quality text andgraphics images on a print medium via direct scanning of a laser beamacross the printer's photoreceptor.

Continuous forms laser printers implement thermal fusing systems toaffix toner to a medium, such as paper. These fusing systems account forapproximately seventy five percent (75%) of the energy consumed by theprinter's print engine. For instance, a typical fusing system mayconsume 11.2 kilowatts (kW) on average, which is equivalent to heatgenerated by 150×75 W light bulbs (or approximately nine times theaverage US household electricity). Thus, for organizations that operateseveral printing systems, the cost of electricity, heat generation, andenvironmental impact are significant operating factors.

Accordingly, a mechanism to recover and utilize a portion of heatgenerated by the print engine is desired.

SUMMARY

In one embodiment, a print engine is disclosed. The print engineincludes a fusing system having a heat pipe to recover heat generated bythe fusing system and transfer the recovered heat back into the fusingsystem.

In another embodiment, a method is disclosed including recovering heatgenerated by a print engine fusing system and transferring the recoveredheat back into the fusing system.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present invention can be obtained from thefollowing detailed description in conjunction with the followingdrawings, in which:

FIG. 1 illustrates one embodiment of a printing system;

FIG. 2 illustrates one embodiment of a printer paper path; and

FIG. 3 illustrates one embodiment of a heat pipe.

DETAILED DESCRIPTION

A mechanism to recover heat generated by the print engine is described.In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. It will be apparent, however, toone skilled in the art that the present invention may be practicedwithout some of these specific details. In other instances, well-knownstructures and devices are shown in block diagram form to avoidobscuring the underlying principles of the present invention.

Reference in the specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the invention. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment.

FIG. 1 illustrates one embodiment of a printing system 100. Printingsystem 100 includes a host system 2 having print software 4 to manageprint jobs and to maintain print job information 6 on the status ofprint jobs managed by the print software. In one embodiment, printsoftware 4 may be implemented using either InfoPrint Manager (IPM) orInfoPrint ProcessDirector (IPPD), although other types of printingsoftware may be used instead.

The term print job as used herein refers to a print job or any componentthereof, including a page of print content, a page including multipleprint items or elements, such as checks, pages, an element on a page,etc. The print job may further include one or more pages, where eachpage has one or more elements, e.g., checks. A page may include a unitof print output, where the page may be outputted on a single piece ofpaper or multiple pages may be outputted on a roll, ribbon or web ofpaper.

Pages may be outputted on a web of paper in different formats, such as2-up duplex. Each of the pages on a web or roll of paper may includemultiple elements. The web of paper may include print jobs, where eachprint job is one or more pages, and where each page includes one or moreelements. In this way, elements and pages may be grouped in print jobs.

The host system 2 may include a processor (not shown) and memory (notshown) in which the print software 4 and print job information 6 isstored for access by the processor. The host system 2 communicates printjobs to the printer 8, where each print job may have one or more pagesor elements, and where each page may have one or more elements. Theprinter 8 includes a first print engine 10 and second print engine 12 toprint output using first 14 and second 16 types of transfer media and areader 18 capable of reading content printed using the first transfermedium 14.

Transfer media 14 and 16 include the material or energy that is used tocause the formation of content on the print medium 20, such as toner,liquid ink, solid ink, dye, wax, heat (which when applied to thermalpaper produces the print content), etc. A print medium 20, such as apiece of paper or other material or textile, is directed through a feedpath 22 by mechanical components of the printer 8, such as rollers,guides, etc. In the feed path 22, the first print engine 10 prints firstcontent of the one or more pages of one or more print jobs on printmedium 20 using first transfer medium 14. The first content that isprinted may comprise an element, a page, a page of elements, etc.

The reader 18 reads the printed first print content to determine thequality of the output. The reader 18 may read each element on one ormore pages to determine the quality of each outputted element. Thereader 18 forwards the print medium 20 to the second print engine 12 toprint second content using the second transfer medium 16 to produceprinted output 24 including one or more print jobs of one or more pageshaving one or more elements printed using both types 14 and 16 oftransfer media.

The printer 8 may include a printer controller 26 to control printingoperations and interface with the printer software 4 to execute thecommands from the printer software 4 and provide feedback thereto. Theprint engines 10 and 12 may include the hardware and/or software tocontrol the printing of content using the first 14 and second 16 typesof transfer media, respectively.

The printed output 24 is forwarded to a post processing component 28which performs various post processing operations on the printed output24. The additional post processing performed on the separated output 32pieces may include stapling, collating, printing, labeling, etc. Thepost processing component 28 then outputs the separated output 32 in afinal form, which may comprise envelopes including the separated output32 pieces. The post processing component 28 may include a postprocessing controller 38 to control post processing operations andinterface with the printer controller 26 and printer software 4 toexecute the commands from the printer software 4 and provide feedbackthereto.

An interface 40 provides intercommunication among the host 2, theprinter 8, and the post processing component 20. The interface 40 mayinclude a network, such as a Local Area Network (LAN), a Wide AreaNetwork (WAN), a wireless network, etc. Alternatively, the interface 40may include a bus interface, parallel interface, serial interface, orother direct line connection. In the embodiment of described herein, thehost 2, printer 8, and post processing component 20 are shown asincluded in separate boxes. In an alternative implementation, theprinter 8 and post processing component 20 may be included in a singlemachine connected via one connection to the host 2. Alternatively, allthree devices 2, 8, and 20 may be included in one machine.

FIG. 2 illustrates one embodiment of a transfer medium 200, such asmedium 14 and 16 shown in FIG. 1. As shown in FIG. 2, transfer medium200 includes a fusing system over which print medium 210 passes in orderto fuse ink on to medium 210. In such an embodiment, the fusing systemis a three-stage system (e.g., low temperature pre-heat, hightemperature pre-heat and hot roll fuse), including pre-heat plate 220,heat rollers 230 and heat transfer roller 240.

As medium 210 travels through the fusing system, it's temperature israised from ambient (e.g., 20° C.) to approximately 70° C. upon passingover pre-heat plate 220, before reaching a temperature of approximately100° C. upon passing through heat rollers 230. After exiting transfermedium 200 and print engine, the 100° C. medium 210 is cooled back downto ambient temperature through heat transfer to the environment.

According to one embodiment, roller 240 is included to reduce heattransfer to the environment by recovering waste heat and returning heatback to pre-heat plate 220. Such a reduction is enabled by heat transfertemperature gradient (e.g., 30° C.) between the hot medium 210 exitingtransfer medium 200 and the low temperature pre-heat plate 220.

In one embodiment, a heat pipe is inserted within roller 240 in order totransport energy from the heat transfer. FIG. 3 illustrates oneembodiment of a heat pipe 300. Heat pipe 300 includes a casing 310, awick 320 and vapor cavity 330. In one embodiment, heat pipe 300 performsa thermal cycle that enables heat to be transferred back to pre-heatplate 220.

During a first step of the thermal cycle, working fluid evaporates tovapor absorbing thermal energy. Subsequently, the vapor migrates alongcavity 330 to the lower temperature end. Next, vapor condenses back tofluid and is absorbed by wick 310, thus, releasing thermal energy.Finally, working fluid flows back to the higher temperature end.

The above-describe mechanism provides recovery of heat generated by aprint engine, thus reducing power consumption and waste heat transferredto the environment.

Whereas many alterations and modifications of the present invention willno doubt become apparent to a person of ordinary skill in the art afterhaving read the foregoing description, it is to be understood that anyparticular embodiment shown and described by way of illustration is inno way intended to be considered limiting. Therefore, references todetails of various embodiments are not intended to limit the scope ofthe claims, which in themselves recite only those features regarded asessential to the invention.

What is claimed is:
 1. A print engine comprising a fusing system havinga heat pipe to recover heat generated by the fusing system and transferthe recovered heat back into the fusing system.
 2. The print engine ofclaim 1 wherein the heat pipe is inserted within a roller.
 3. The printengine of claim 2 wherein the fusing system further comprises: apre-heat plate to heat a medium to a first temperature; and heat rollersto heat the medium to a second temperature.
 4. The print engine of claim3 wherein the heat pipe recovers waste heat from the medium at thesecond temperature and transfers the heat to the pre-heat plate.
 5. Theprint engine of claim 1 wherein the heat pipe comprises: a casing; awick within the casing; and vapor cavity within the wick.
 6. The printengine of claim 5 wherein fluid in the wick at a high temperature sideof the heat pipe evaporates to vapor within the vapor cavity.
 7. Theprint engine of claim 6 wherein the vapor migrates to a low temperatureside of the heat pipe within the vapor cavity.
 8. The print engine ofclaim 7 wherein the vapor condenses to the fluid at the low temperatureside of the heat pipe within the vapor cavity.
 9. The print engine ofclaim 8 wherein the wick absorbs the fluid.
 10. The print engine ofclaim 9 wherein the fluid flows back to the high temperature side of theheat pipe within the wick.
 11. A method comprising: recovering heatgenerated by a print engine fusing system; and transferring therecovered heat back into the fusing system.
 12. The method of claim 11wherein recovering the heat comprises a heat pipe recovers waste heatfrom a print medium at a first temperature and transferring the heat toa pre-heat stage of the fusing system.
 13. The method of claim 12wherein recovering the heat comprises fluid in a wick at a hightemperature side of the heat pipe evaporating to vapor within a vaporcavity of the heat pipe.
 14. The method of claim 13 further comprisingthe vapor migrating to a low temperature side of the heat pipe withinthe vapor cavity.
 15. The method of claim 14 wherein transferring theheat comprises vapor condensing to the fluid at the low temperature sideof the heat pipe within the vapor cavity.
 16. The method of claim 15further comprising: the wick absorbing the fluid; and the fluid flowingback to the high temperature side of the heat pipe within the wick. 17.A printer transfer medium comprising: a pre-heat plate to heat a printmedium to a first temperature; heat rollers to heat the print medium toa second temperature; and a heat transfer roller including a heat pipeto recover heat from the print medium and transfer the recovered heatback to the pre-heat plate.
 18. The printer transfer medium of claim 17wherein the heat pipe is inserted within a roller.
 19. The printertransfer medium of claim 17 wherein the heat pipe comprises: a casing; awick within the casing; and vapor cavity within the wick.
 20. Theprinter transfer medium of claim 19 wherein fluid in the wick at a hightemperature side of the heat pipe evaporates to vapor within the vaporcavity.